Valve mechanism



mm a FWD n F Nov. 7, 1950 INVENTOR. ROBERT E :SMITH W rm Patented Nov.7, 1950 2,528,796

VALVE MECHANISM Robert F. Smith, Detroit, Mich, assignor to Chrysler.Corporation, Highland Park, Mich, a-

corporation of Delaware Application December 29, 1944, Serial No.570,299

1 Claim.

This invention relates to an improved valve mechanism, particularlyapplicable to hydraulic brake systems although not limited thereto inits broad aspects.

A hydraulic brake system of the type applicable December 29, 1944 nowPatent No. 2,447,142 to motor vehicles includes a master cylinder fromgranted August 17, 1948. g which a fluid operatin medium is forced underThe master cylinder provided by the casin i2 pressure to wheel brakecylinders. A double actincludes a fluidreservoir ii. at the upperportion ing valve mechanism is preferably employed thereof and apressure cylinder iii'at the lower which permits fluid to leave thecylinder but re m end portion. A flexible, bell-shaped boot lil'closesstrains the return thereto in order to maintain the upp d portion of thecasi e O a predetermined pressure in the wheel cylinders. having aperipheral flange abutting and secured An object of the invention is theprovision of to casing flange by screws 29, and a central openanimproved valve mechanism comprising a miniing receiving a pistonactuating rod 2i connected mum number of cooperating parts which do notat 22 to the pedal. it. A filter 22 has a cylinnecessitate exactindimensional relationship for drical filtering portion into which the rodti successful operation of the mechanism. tends and a flange seated onand secured tothe More particularly, an object of the invention bottomwall of thereservicr ll; 1 is the provision of a double acting valveniccha- The upper end of the cylinder 56 is provided nism includingcooperatively engaged parts, one with a piston 23 and a packing cup 2dabutting thereof being adapted for deflection into and the lower face ofthis-piston. the cylinder 53 beout of sealing relation with the othterdurirv oping in fluid communication with the-reservoir ll eration of themechanism, the parts being so co-nby means of the registerin openings 25and toured and engaged that the defiectible part 9 respectively in thepiston and cup. The piston tends to maintain the sealing relation andrela- 23 is provided with a seat?! inclined downward.- tive expansion ofthe parts does not resultin ly and inwardly toward and surrounding theunintended disruption of the sealing relation. opening 25, which seat isengaged by the end oi A still further object of the invention is the theend of the rod 2! to close the opening 25 provision of a valve mechanismof the foregoing to the passage of fluid theretnrough during the typewherein the aforesaid cooperating parts of '30 pressure stroke of therod H as will be herein the mechanism are provided with fluidpassageafter more fully set forth. forming openings s0 arranged as tofacilitate in- Fluid is discharged from the cylinder 58 to the tendeddeflection of the deflectible part into and fluid lines leading to thewheel cylinders 53 out of its sealing relation. through a port-formingopening 28 at the lower Other objects and advantages of the inventionend of the casing l2. Associated with this port will be more apparentfrom the following descripis a valve mechanism including a. resilientlyyieldtion taken in connection with the accompanying able member 29adapted to rest against a valve drawings, wherein: seat 3d surroundingthe port and a relatively rigid Fig. 1 is a schematic view of ahydraulic brake member 3i engaging the member 29. A coil systemembodying the'invention. 0 spring 32 is interposed between the pistonseal- Fig. 2 is an enlarged elevational view, mainly ing cup gs a tmember 3 fo urgin the in section, of the master cylinder of Fig. 1 andmember 29 against the Valve Seat 39 ears showmg F Valve mecheimsmstruckfrom the member 3i serving to limit shift- F1g. 3 is an enlarged Viewtaken on line 33 of mg of the spring. The mbe 29 is preferably f Ommmgthe P p I formed of rubber or a rubber-like material and i 4 1Sfragmentary Semlonal VleW taken is provided with acentral openin 33registering Onlme with the ort The member 29 i t d b Referring to thedrawings, the invention is p l s pare embodied in a hydraulic brakesystem of the type twefm maximum .th1cknes s adJacent the cuterparticularly adapted for motor vehicles and which Penphery to a mmlmumthlckness at the includes a casing I2 providing the master cylinmg 33and the upper face thereof engaged by der, wheel brake cylindersindicated at [3, conthe member 35 is inclined doWnWaldly and innected byfluid lines to the master cylinder, and Wardly from the aforesaid p p e0 e pe an operating pedal I 3 pivoted at E5 to a support ing In Order130 eXert p e against the IS. The master cylinder and its associatedopentire surface of this engaged face the member crating structure,other than the specific valve mechanism hereinafter set forth, forms thesub.- ject matter of application of Robert F. Smith and Bruce E. Clark,Serial No. 579,298 filed the member 29.

3! is correspondingly contoured at its engaging face.

The member 2 9 has a portion thereof overhanging the port-formingopening 28 and the member 3! has a plurality of apertures 34therethrough which register with the overhanging portion of As thepiston 23 and cup 24 are moved downwardly by corresponding movement ofthe rod 21 by the pedal M, fluid trapped in the cylinder I8 by sealingengagement of the rod end with the piston seat 2'! passes through theapertures 34 forcing the central portion of the member 29 out of itsnormal sealing engage: ment with the rigid member 3l and allowing thefluid to pass through th opening 33 to the portforming opening 28 to thewheel brake cylinders for application of the brakes. Upon release of thepedal and return thereof to normal position the rod 2| will be movedupwardly thereby; however, the piston 23 will not be positivelycorrespondingly moved thereby but will be returned to illustratedposition by the spring 32, the filter 22' limiting upward returnmovement. As the pressure is relieved by upward movement of the pistonthe portion of the member deflected as aforesaid from the member 3| willreturn to its illustrated full-line position through its inherenttendency to so return, the fluid pressure from the wheel brake cylindersand fluid lines also acting to.

effect this return. The valve will be moved from its seat when thepressure trapped in the lines and wheel cylinders is suflicient toovercome the force of the spring 32, whereupon fluid will then 7 passbetween the outer peripheral edge of the members 29, 3! and the wall ofthe cylinder into 1.

Return of the actuating rod to its the latter. normal position uncoversthe opening 25 in the piston 23 to establish fluid communication betweenthe cylinder !8 and reservoir 11,

In the illustrated embodiment the resilient member 29 is freelexpansible laterally with respect to'the member 3 i, the outerperipheral edge of the former being spaced from the latter and notconstrained thereby. Freedom for expansion of the member 29 due to heator reaction to its association with the fluid operating medium avoidsunintended opening of the valve resulting from buckling of the resilientmember due to constraint, as by the member 3 I, against expansion.

Although but one specific embodiment of the invention is herein shownand described, it will be understood that various changes in thesize,shape and arrangement of parts may be made without departing fromthe spirit of the invention.

I claim:

A valve mechanism including a valve seat and mined fluid pressure toprovide passage through the aperture and opening in one direction, and acoil spring urging said members into engagement and said yieldablemember against said seat, one end of said spring being seated on saidrelative rigid member and the latter having a plurality of ears integraltherewith cooperating with said spring one end for limiting shifting ofsaid spring relative to said'relative rigid member, said ears beingdisposed in the space bounded by said spring one end.

ROBERT F. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent: v V

UNITED STATES PATENTS Name Date Bowman Jan, 19, 1932 Loweke Nov. 1, 1932Chase June 26,1934

Number Hatcher Aug. 20, 1935 Rosenberg Oct. 18,1938 Heidloff NOV. 1,1938 Carroll July 23, 1935 I

